5. Maintenance & Check 
5-3 
 
5.5 Troubleshooting 
The table below shows the principal symptom, the cause, and measurements. As a result, request the repair 
to our company or our agency when it is not possible to recover to normal operational condition. 
Symptom Cause  Measurements 
The screen doesn't appear 
even if power switch is 
pressed. 
The breaker of AC100-230V of the ship is 
"OFF". 
Make the breaker of AC100-230V of the ship 
"ON". 
The main switch in processing unit is off  Check this switch and turn on. 
The Display processing unit is faulty.  Contact us or your distributor. 
Low brightness  brighten a screen 
The disconnection of the power supply AC 
inboard cable or the screw in the 
connecting terminal has loosened. 
Repair the cable.   
Tighten the screw in the connecting terminal 
surely. 
The fuse is blown.  Replace the fuse. 
The brightness is not changed  The display unit is faulty.  Contact us or your distributor. 
Software is not working properly 
No buzzer sound and 
key-tone is emitted. 
The display unit is faulty.  Contact us or your distributor. 
Software is not working properly 
Alert setting and key ack setting is off  Contact us or your distributor because 
setting menu is for service engineer. 
The depth value is not 
displayed.  
Only the oscillation line is 
displayed in the image of a 
standard mode. 
Actual sea bottom is deeper than the 
setting of range. (out of range) 
Make the range setting AUTO. or, change 
the range setting manually and adjust it. 
The transducer cable has been 
disconnected. 
Repair the cable. 
The depth value is not 
displayed.  
The sea bottom echo is 
slightly recorded by the image 
of a standard mode. 
The sensitivity setting is too weak.  Make the sensitivity setting AUTO. or, raise 
sensitivity. 
Sea bottom is mud (weak stratum).  Make the sensitivity setting AUTO. or, raise 
sensitivity. 
The oyster and the barnacle adhere to the 
transducer. 
Remove the adhesion thing of the transducer 
at dry-dock. 
The cable disconnection of the transducer 
or the screw in the connecting terminal has 
loosened. 
Check whether for be disconnected of the 
one side of the transducer.   
Tighten the screw in the connecting terminal 
surely. 
The depth value is not correct.  A set value of the draft adjustment is not 
correct. 
Set a correct value. 
The depth value is not correct. 
In the image of a standard 
mode, the record mistaken in 
a middle layer as sea bottom 
appears. 
The sensitivity setting is too strong.  It is recorded to garbage in water, dirt, and 
plankton's layers that sensitivity is too high, 
and recognizes sea bottom this.   
Make the sensitivity setting AUTO.   
Or, lower sensitivity. 
There are a lot of records of 
the noise. 
 
Noise generated from dynamo.  Check the dynamo. 
The main unit earth is imperfect.  Check the main unit earth. 
External interference noise.  The influence of the underwater sonic 
prospecting equipment of another ship has 
been received.   
This symptom is not a trouble of this 
equipment and originates in an external 
factor. 
The echo displayed on the 
screen becomes all cyan. 
Transmission is stopped.  Turn off the power of the display processing 
unit and restart it. 
When the problem persists, contact us or 
distributor.